Extended Attribute Provider
Introduced in SML3.8, ISMLExtendedAttributeProvider is an interface
that allows any modded asset to offer additional data to other mod systems without involving a specific class in the hierarchy.
Consider the base game’s FGItemDescriptorNuclearFuel and FGItemDescriptorBiomass classes.
Nuclear Fuel adds new 2 properties to the standard item descriptor, while Biomass adds none.
However, because they are implemented as full classes, it’s impossible to have an item which is both nuclear fuel and biomass.
As an interface, the Extended Attribute Provider can be used without locking you out of using another class as the parent.
Usage
To use the interface, implement it on your asset.
For blueprints, this is done in Class Settings > (Interfaces subheading) Implemented Interfaces > Add.
Features
As of SML3.8, the only system that uses this interface is the Content Tag Registry.